Does Water Float?

When you pour a small amount of water into a larger amount of water, what happens to the smaller amount of water? Does it float on top, sink to the bottom, or mix in somewhere in the middle? Does it depend on whether the water came from the same source or is the same temperature? What about when you put ice in water? When it melts, where does it go in relation to the water you placed it in? More importantly, is there any way to really know and does it even matter? Probably not, but now that it’s been brought up, wouldn’t you like to know?